External quality assessment schemes for toxicology

Area of Science:

• Clinical Toxicology
• Analytical Chemistry
• Forensic Science

Background:

• Routine biochemical analysis relies on external quality assurance (EQA) schemes for quantitative performance monitoring.
• Existing EQA schemes often lack sufficient toxicological range or appropriate matrices (e.g., whole human blood).
• Specialist EQA schemes exist for drugs of abuse in urine and hair analysis.

Purpose of the Study:

• To evaluate the limitations of current EQA schemes in toxicological analysis.
• To highlight the need for EQA programs that encompass both analytical and interpretative aspects of toxicological investigations.
• To introduce pilot schemes offering broader toxicological analyte coverage in human blood.

Main Methods:

• Review of existing EQA schemes for biochemical and toxicological analyses.
• Description of a pilot scheme by UKNEQAS for quantitative determination of opioids, benzodiazepines, and tricyclics in human blood.
• Identification of EQA providers offering integrated analytical and interpretative case studies.

Main Results:

• Current EQA schemes may not fully cover toxicological concentration ranges or use ideal matrices.
• Specialized EQA schemes exist but often focus on specific matrices or analyte types.
• Integrated EQA programs combining analytical and interpretative case studies are available from providers like UKNEQAS and KKGT.

Conclusions:

• Existing EQA schemes provide valuable data on analytical technique performance but do not fully address the integrated nature of toxicological case investigations.
• The development and adoption of EQA programs that incorporate interpretative case studies are essential for improving the overall quality of toxicological analysis.
• These comprehensive EQA programs support clinical and forensic advice by evaluating the integrated analytical and interpretative processes.